【 Weak current College 】 compressor failure causes and countermeasures

Compressor is used to improve the gas pressure and mechanical conveying gas. From the energy point of view, the compressor is the prime mover of power can shift to gas pressure energy of the machine. With the development of science and technology, the application of pressure to the increasingly widespread, allowing the compressor in the national economy in the construction of many departments to become one of the essential key equipment. Compressor in operation process, inevitably some failures, and even accidents. Failure means that the compressor is running in an abnormal situation occurs, upon ruled compressor can resume normal work accident refers to the damage occurred. The two are often related, if encountered failure does not exclude it in a timely manner will result in a major accident.
Common failures and their causes and measures

Insufficient exhausting amount: amount is insufficient exhausting and compressor gas comparison of design. Main can be considered from the following areas:

1. the air inlet filter: scale plug, so that the exhaust volume reduction; suction pipe is too long, diameter is too small to cause breathing resistance increases the impact on the volume that you want to regularly clean the filter.

2, the compressor speed reducing the exhaust volume reduction: improper use of air compressors, air compressor discharge capacity is based on a certain altitude, suction temperature, humidity, when it uses more than the standard plateau, inspiratory pressure decrease, reduce the exhaust volume inevitable.

3, cylinder, piston, piston ring wear, variance, so that the gap increases, leakage rate increases, the impact on the exhaust volume. Attributable to normal wear, the timely replacement of wearing parts such as piston ring, etc. Is not installed correctly, there is no suitable clearance should be granted according to the drawing, if not corrected, the desirable experience drawing, for piston and cylinder circumference of gap between, such as cast iron piston, cylinder clearance values for diameter 0.06/100 ~ 0.09/100; for aluminium piston, clearance of gas path diameter 0.12/100 ~ 0.18/100; steel piston preferable aluminium alloy piston of a smaller value.

4, the stuffing is not strict air leakage to reduce production. The first is the time of manufacture of the stuffing box itself; secondly noncompliance may be due at the time of installation, the piston rod and stuffing Center on is not good, abrasive, scratching, etc cause leakage; in General stuffing box office, add oil, it takes on the lubrication and sealing, cooling effect.

5. compressor suction and discharge valve failure to exhaust volume. The seat and the valve plate restaurant in fell into metal debris or other incidentals, close, forming a leak. This not only affects the exhaust volume, but also influence the level of pressure and temperature between; seat and the valve plate contact strictly formed leakage and affected the exhaust volume one is manufacturing quality problems, such as valve warping, the second is because the seat and the valve plate wear serious and formation of leakage.

6. valve spring force and gas power matching is not good. Stretch too strong then slow opening of the valve plate, elastic too weak the valve plate close is not prompt, these not only affect the volume, but also to the power and the valve plate, springs of life. At the same time, also affect the gas pressure and temperature changes.

7, compact valve pressure force. Clamping force is small, and, of course, you want to leak too tight or not, will make the hood deformation and damage, normally pressing force available under-calculation: p = π/4 k D 2 P 2, D is the diameter of the valve cavity, P2 is the largest gas pressure, K to a value greater than 1, generally take 1.5 ~ 2.5, when K = 1.5 low voltage ~ 2.0, hypertension K = 1.5 ~ 2.5. such takes K, practice shows that it is good. Valve has a fault,bonnet bound fever, while pressure is not normal.

Exhaust temperature is normal exhaust temperatures not normally refers to it is higher than the design value. Effects from theory motivated, exhaust gas temperature increases: intake air temperature, the pressure ratio, as well as the compression index (for air compression index K = 1.4). Actual situation affected the suction temperature high of factors such as: low intermediate cooling efficiency, or cooler effect of many within the scale to the heat, the temperature of the air behind the stage will be high, the discharge temperature can also be high. Valve leakage, piston leak gas, not only affects the exhaust temperature, but also makes the stage pressure change, as long as the pressure ratio higher than the normal value would make the exhaust temperature rise. In addition, the water shortage water-cooled machine, or not enough water will make the exhaust temperature rise.

Pressure is abnormal and exhaust pressure reducing exhaust gas compressor at rated pressure does not meet the consumer's flow requirements, the exhaust pressure must reduce, reduce the exhaust pressure is the phenomenon, its essence is the exhaust volume does not meet users ' requirements. At this point, had to change a single exhaust pressure are the same, but the exhaust volume big machine. Impact-level pressure is abnormal mainly valve leakage or piston leak gas, wear should be from these areas to find the causes and the measures taken.

Abnormal noise compressor if certain components fails, an exception will be issued for the General, operators can identify unusual noises. Piston and cylinder head clearance is too small, direct impact; piston rod and piston connection nut loose or trip, the piston end wire plug Cypress, piston up bunch of dynamic collision in the cylinder head, cylinder falling into metal debris accumulation of water in the cylinder can be issued within the cylinder rap. Crankcase-bolts within the crankshaft, connecting rod bolt, nut, cross head bolt, tripping, broken, shaft diameter wear serious gap, crosshead and bushings with gap is too large or wear, and so on can be issued within the crankcase. Exhaust valve plate broken, loose or damaged valve spring, load regulator tuned properly and so on can be issued within the valve cavity rap. Thus to find fault and to take measures.

Overheating faults in the crankshaft and bearings, crosshead and a skateboard, fillers and piston rod, friction, temperature exceeds the set of numbers called overheating. Overheating their consequences: a is accelerating the friction and wear between the Vice-President, the second is a thermal heat accumulate due to burning of friction surface straight and burning have caused significant machine. Cause the cause of the overheated bearing: bearing and axle journal Lamination are notUniform or contact area is too small; the crankshaft bearing crabbing, lube oil viscosity is too small, blocked, causing oil pump defective; broken oil without installation, not looking good leveling, spindle and motor axis no alignment, there are two axis tilt.

Compressor accidents

Crankshaft fracture: most of its faults and the crankshaft of the axle journal fillet Department, owing largely are the following: fillet is too small, r < 0.06d (d for crank shaft neck); heat treatment, round corners, so that is not processed to produce the stress concentration at the junction; rounded processing irregular, there is a local section mutation; long-term overload, and the user in order to increase the yield, increased speed, so that the force conditions worsen; material itself has a defect, if there are sand castings, shrinkage, and so on. In addition the crankshaft oil holes on the initiation and broken is visible.

Breaking: connecting rods are the following: connecting rod bolt breaks, its causes are: Rod screw plastic deformation produced long-term use; screw head or nuts and big head end bad produce eccentric loads, the load can be large to be pure axial bolt force seven times, therefore, is not allowed to have any slight skew, contact should be evenly distributed, disconnected from the point of maximum distance shall not exceed 1/8 circle i.e. 450; bolt material processing quality.

Piston rod fault: the site is the main faults and crosshead connected thread and fasten the thread of the piston, the Department is the weak link in the piston rod, if as a result of the negligence of the design, manufacture and operation of sloppy because of fracture on more often,. If during the warranty of design, manufacture, materials are not the problem, when you install the pre-tightening force shall not be too large, otherwise the maximum force to achieve yield limit will break when the piston rod. In the long run, since the transition and wear, for cylinder horizontal column in the piston will sink, thus enabling connection thread generates additional load, and then run it, it is possible to make the piston fracture, maintenance should pay special attention. In addition, because of other parts of the damage, so that the piston was strong shocks, which may make the piston fracture.

Rupture of the cylinder, cylinder head: main reasons: for water-cooled machine, parking in winter operation, to forget the cylinder, cylinder head cooling water, cooling water will freeze and broke the cylinder and cylinder head, especially in the northern region of China, parking must be ducking, cooling water; water due to the outage but have not found the time to make the cylinder temperature rise, and suddenly into the cooling water, make the cylinder was exploding; the dead points gap is too small, loose piston nuts, and falling into the tank of a metal and piston silk wall prolapse reasons make the piston impact cylinder head to rupture.

Combustion and explosion have oil-lubricated compressor is often produce carbon problem, this is the last thing we want,because the charcoal will void the piston ring card in the slot, the valve is not functioning as well as reduce the airflow channel area, and to increase the resistance under certain conditions the charcoal will burn, causing the compressor of the incident. Therefore, the cylinder of lubricating oil cannot supply too much, not without a good filter that contains a lot of dust inhalation cylinder, forming carbon and contains more of volatile gas contact resulted in an explosion. In order to prevent burning, explosion, be sure to plan maintenance, periodic cleaning of the tank and pipes grease stain.

In addition, compressor combustion and explosion accidents there are the following reasons: the compressor in hydrogen, oxygen, nitrogen and hydrogen load test before, no use of nitrogen will air low-voltage driving clean and cause an explosion. Because of a lack of operational knowledge, does not open after driving into the tank valve compressor, resulting in a rapid rise in the exhaust pressure led to the explosion. Therefore, to prevent such accidents, the drive must be familiar with the practice, drive, pay close attention to the manometer. In general the best small and medium-sized compressor, air compressor to be this pipeline of gate valve cancelled, leaving only the check valve. In addition, the compressor operator should conduct training pre-work.

As a result of compressor pressure level valve does not close, the high temperature of the gas cylinder, exhaust valve returned near high temperature, when there is a deposited there, that would cause an explosion. To avoid an accident, you must repair the exhaust valve, check the leak site and eliminate faults.